Linked opendata - 24062011
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Linked opendata - 24062011



Presentation done at the Paris City Hall on june 23th

Presentation done at the Paris City Hall on june 23th



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Linked opendata - 24062011 Linked opendata - 24062011 Presentation Transcript

  • Linked Data for Open Cities Loïc DIAS DA SILVA [email_address] is your data 5 ? Amsterdam Barcelona Berlin Paris
  • - deeply passionate about the web, its history, its future.. - software engineer, GNU/Linux addict - responsible for the API team in Viadeo ( ) - not a designer (as you will see soon..) - semantic web evangelist, open-source software user - created some weeks ago the webapp
    • The semantic web paradigm Paris Semantique feedbacks Linked Open Cities
  • WEB before ~2000 the document web
  • webmasters readers HTML Netscape unidirectional to link documents
  • WEB '2.0' the social web
  • user-centric prosumers crowd sourcing participation friends sharing media to link people API
  • Web of Data use-case
  • The nicer story i've never read ! I want more !
  • I want more ! OK !
  • ?!?!?! Highly ranked !
  • ???? Recommended to you
  • :~(
  • = ?
  • ok !
  • media suitable for little girls searching for princess stories ...
  • Web of Data
  • to link knowledge
  • <subject> <verb> <complement> a unit of information can be atomicized : as of RDF vocabulary : <subject> <predicat> <object> an RDF triple
  • [<subject>] [<predicat>] [<object>] ” lorem ipsum” lang type all is UR I
  • <subject> <predicat> <object> express the semantics using ontologies FRBR
  • [<subject>] [<predicat>] [<object>] Loïc ” is a” person < 002l8n979djxjeg> < type> viadeoprofile: 002l8n979djxjeg < Person> rdf: type foaf: Person
  • owl: sameAs rdf: type foaf: interests (foaf: interests) dc: creator (rdf: type) foaf: knows owl: sameAs (foaf: knows) foaf: name foaf: nickname viadeoprofile :loic.diasdasilva facebook :loic.diasdasilva foaf: Person wikipedia: Semantic_Web foaf: Person foaf: Person w3cpeople :Berners-Lee viadeoprofile :jean-philippe.clement1 twitter :opendataParis ” Loïc DIAS DA SILVA” ” Mglcel”
    • RDF expresses graphes, this is not about format several serializations
    < rdf:RDF xmlns:rdf=&quot; #&quot; xmlns:foaf=&quot; &quot;> < rdf:Description rdf:about =” ”> < rdf:type rdf:resource =”” /> < foaf:name >Loïc DIAS DA SILVA</ foaf:name > </ rdf:Description > </ rdf:RDF > RDF/XML @prefix foaf : < > . @prefix viadeoprofile : < > . viadeoprofile :002l8n979djxjeg a foaf :Person ; foaf :name ”Loïc Dias Da Silva” . TURTLE { &quot; &quot; : { &quot;;: [ { &quot; type &quot; : &quot; uri &quot; , &quot; value &quot; : &quot;; } ], &quot;;: [ { &quot; type &quot; : &quot; literal &quot; , &quot; value &quot; : &quot;Loïc Dias Da Silva&quot; } ] } } JSON
    • RDFa : RDF in HTML attributes
    <div> <a href=” ”> Loïc Dias Da Silva </a> </div> xHTML <div xmlns:foaf=&quot; &quot; > <a href=” ” class=”foaf:Person” property=”foaf:name” > Loïc Dias Da Silva </a> </div> xHTML + RDFa
    • SPARQL : query RDF graphes
    rdf: type foaf: name @prefix foaf: < > @prefix wikipedia: < > SELECT ?theName WHERE { ?person a foaf:Person . ?person foaf:interests <wikipedia:Semantic_Web> . ?person foaf:name ?theName . } foaf: interests viadeoprofile :loic.diasdasilva foaf: Person ” Loïc DIAS DA SILVA” wikipedia: Semantic_Web
  • SPARQL PREFIX pswcity: <> SELECT DISTINCT ?name ?add_number ?add_wayname WHERE { ?s pswcity:name ?name . ?s pswcity:address ?address. ?address pswcity:address_number ?add_number . ?address pswcity:in_way ?way. ?way pswcity:fullName ?add_wayname . FILTER ( ?s = <>) . }
  • Linked data principles
    • Use URI s to identify things.
    • Use HTTP URI s so that these things can be referred to and looked up (&quot;dereferenced&quot;) by people and user agents.
    • Provide useful information about the thing when its URI is dereferenced, using standard formats such as RDF/XML.
    • Include links to other, related URIs in the exposed data to improve discovery of other related information on the Web.
  • “ Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch.”
  • ? ? ? ?
  • A big work has to be done in order to semantize current data : - Different values for identifiation, ex Districts: '20e', 'XXe', '75020', 'PARIS 20', street names, etc.. - Many datasets not documented, semantization = meaning, is difficult - Some cells containing differently formatted values, multiple lines on multiple cells - ~80% of ESRI geo data without metadata Two main issues to resolve : Objects identification Types determination
  • ★ make your stuff available on the Web (whatever format) under an open license ★★ make it available as structured data (e.g., Excel instead of image scan of a table) ★★★ use non-proprietary formats (e.g., CSV instead of Excel) ★★★★ use open standards from W3C (RDF and SPARQL) to identify things, so that people can point at your stuff ★★★★★ link your data to other data to provide context TBL : << The Semantic Web isn't just about putting data on the web. It is about making links, so that a person or machine can explore the web of data.  With linked data, when you have some of it, you can find other, related, data. Like the web of hypertext, the web of data is constructed with documents on the web. However,  unlike the web of hypertext,  where links are relationships anchors in hypertext documents written in HTML, for data they links  between arbitrary things described by RDF,.  The URIs identify any kind of object or  concept.   But for HTML orRDF, the same expectations apply to make the web grow >>
  • Linked Open Cities proposal standard machine-readable material shared semantics semantic web
  • Linked Open Cities : 1st step standard machine-readable material
    • object-oriented
    • unique identifiers for each object in each city
    • clear object types
    • clearly identified data (not mixed in a single field for instance)
    • clear data types (integers, enums, dates, strings [names, titles, ..], years, standard units)
  • Linked Open Cities : 2nd step shared semantics
    • base framework : shared object types & data types
    • links inside texts, between objects
    • one page for each object
    • begin to find links to related content from other open cities or media repositories
  • Linked Open Cities : 3rd step semantic web
    • one simple, basic, but shared ontology, linked to some well-recognized ontologies
    • a shared sub-ontology for common concepts
    • a specific sub-ontology per city for dedicated concepts
    • RDF transformation of the data
    • industrialize the linking of objects (In & Out)
    • SPARQL endpoint opening
    • No need for specific API (but already possible) !
  • Thanks for you attention ! So, will your data be 5 ?